A known sceptic of Andrew Lansley's big bang health reforms, Sir David Nicholson had a chance to halt the controversial health secretary's plan when he was called in by the Tory enforcer Oliver Letwin and his Lib Dem counterpart, Danny Alexander, for a meeting in the Treasury in late 2010.

The pair asked him whether they should they continue with the reforms given the emerging and troubling opposition from both the public and the medical profession. The answer was an unequivocal yes. He was, in the words of a former colleague, "pitch perfect his master's voice".

The response was typical of a son of a plasterer who ended up serving five secretaries of state and three prime ministers. He started work for the NHS as a graduate trainee in the same year he joined the Communist party – inspired by his support for the anti-apartheid struggle.

Although he let his party membership lapse in 1983, Nicholson enjoyed playing on his "Stalinist" credentials – seeing the health service as best run by "command and control" from his perch in the Department of Health.

He was brought in by Labour's health secretary Patricia Hewitt when the NHS was struggling to keep its finances in order. New Labour had originally wanted a US healthcare boss to step in, but Nicholson got the top job. Surprised to be in the post, he proved remarkably effective.

Under his leadership NHS spending was reined in while waiting times were brought down. He also successfully brought in a programme to tackle hospital infections. His encyclopedic knowledge of the NHS meant new health secretaries always relied heavily on his advice. Such was his influence that people joked about the Nicholson Health Service. When the coalition talks were under way in May 2010, Nicholson occupied the health secretary's seat at the Department of Health, joking: "We are real masters now."

But Nicholson was ever faithful to his political bosses. Even when Lansley was on the verge of being sacked by Downing Street, Nicholson continued to text support to the beleaguered cabinet minister.